This invention relates to a system for crimping metal sheets and more particularly to a female die designed for use in crimping metal sheets.
It is well known that metal sheets can be joined by devices for joining the metal sheets by a riveting type method utilizing mating dies in which the counter edges provided by the female die are yieldable. Such devices have been shown in U.S. Pat. No. 4,614,017, xe2x80x9cDevice For Joining Metal Sheets By A Riveting-Type Methodxe2x80x9d, issued Sep. 30, 1986, to Gerdxe2x80x94Gxc3xcrgen Eckold and Hans Maass. This patent discloses in general that female dies having edges, which are yieldable, can be used with a male die to form joints. These joints are generally formed by cutting the metal sheets by interaction of the male die and the edges of the female die with the edges of the female die then yielding outwardly so that by further interaction of the dies, a portion of the cut material is spread by material flow to form a strong joint in the vicinity of the cuts and the material flow. Such techniques are referred to generally as xe2x80x9ccrimpingxe2x80x9d. Crimping is widely used to join thin metal sheets of a variety of types for a variety of applications. Considerable effort has been directed to the development of effective and economical tools for use for this purpose.
Unfortunately, the fabrication of the female dies is relatively expensive and many of the dies currently in use are not readily repairable, nor are they readily adjusted to accommodate various thicknesses of metal sheets and the like. Accordingly, a continuing effort has been directed to the development of a better system for joining metal sheets by crimping, and in particular, a considerable effort has been directed to the development of an improved female die.
According to the present invention, a female die for use by interaction with a male die to join metal sheets together by interaction of the dies to cut or slice through the sheets to form portions of the metal sheets which are spread by material flow by the interaction of the dies to prevent separation of the metal sheets is disclosed. The female die comprises an anvil member having a first and a second end and including an anvil surface at its first end, and a base at its second end; at least two side plates positioned on the anvil member to restrict movement of the side plates toward the second end during interaction of the dies, the side plates being resiliently biased toward the anvil surface to permit movement of the side plates away from the anvil surface during the spreading of the portions of the metal sheets, and extending a selected distance beyond the anvil surface in a direction away from the base; and, at least one spring member supported by the base and in biasing engagement with each of the side plates to resiliently bias the side plates toward the anvil surface.
The present invention further includes a system for joining metal sheets together by interaction of a male die and a female die to cut or slice through the sheets to form portions of the metal sheets which are spread by material flow by the interaction of the dies to prevent separation of the metal sheets, the system comprising:
a) a female die including an anvil member having a first and a second end and including an anvil surface at its first end, and a base at its second end; at least two side plates secured to the anvil member to restrict movement of the side plate toward the second end during interaction of the dies, the side plates being resiliently biased toward the anvil surface to permit movement of the side plates away from the anvil surface during the spreading of portions of the metal sheets, and extending a selected distance beyond the anvil surface in a direction away from the base; and, at least one spring member supported by the base and in biasing engagement with each of the side plates to resiliently bias the side plates toward the anvil surface;
b) a male die comprising a punch having cutting edges and configured to interact with the side plates of the female die to cut the metal sheets to form portions of the metal sheets which are spread between the punch and the anvil surface; and,
c) a device for moving the male die toward the female die at sufficient pressure and velocity for interaction with the female die to cut or slice through the metal sheets to form portions of the metal sheets which are spread by material flow by the interaction of the dies.